The wireless communication technology for increasing portable electronic devices (such as smart phone, tablet, and notebook) has obtained more attention in recent years, and the quality of the wireless communication usually depends on the efficiency of antenna in the portable electronic device. Therefore, it is important to improve radiation efficiency of the antenna and to be able to easily adjust overall frequency.
In addition, with the coming of the next generation of communication technology, 5G licensed assisted access (LAA), the design of the existing antenna structure, such as planar inverted-F antenna (PIFA), may not meet the band requirements of the 5G communication system. As disclosed in U.S. Pat. No. 8,552,912 “Antenna for thin communication apparatus”, the ground segments 112, 114 are used to increase the bandwidth. However, the 5G communication system has a higher demand for band and bandwidth, and the antenna disclosed in said patent cannot cover both the bands of 4G and 5G.